#use "context.decls"

let list_compress : list -> list |>
{   [] => []
  | [0] => [0]
  | [1] => [1]
  | [0;0] => [0]
  | [1;1] => [1]
  | [2;0] => [2;0]
  | [1;0;0] => [1;0]
  | [0;1;1] => [0;1]
  | [2;1;0;0] => [2;1;0]
  | [2;2;1;0;0] => [2;1;0]
  | [2;2;0] => [2;0]
  | [2;2;2;0] => [2;0]
  | [1;2;2;2;0] => [1;2;0] 
} = ?
